An acceleration device is known in the art, according to which an accelerating condition of an automotive vehicle is controlled depending on a stepping amount of an acceleration pedal operated by a vehicle driver. In the known acceleration device, the stepping amount of the acceleration pedal is detected by a rotational angle of a pedal shaft, which is connected to the acceleration pedal. For example, an acceleration device is disclosed in Japanese Patent Application No. 2012-222056 (corresponding to U.S. patent application Ser. No. 14/045,374), which is not published before the filing date (Dec. 25, 2013) of the present application in Japanese Patent Office. The acceleration device of the above patent application has a pedal rotating member, which is fixed to a pedal shaft rotatably supported by a supporting body. A forward end of the pedal rotating member is brought into contact with an inner wall surface of the supporting body in order to limit a fully closed position and/or a fully opened position of the acceleration pedal.
In the acceleration device of the above patent application, the forward end of the pedal rotating member may be broken away from a boss portion of the pedal rotating member, when the forward end of the pedal rotating member is strongly brought into contact with the inner wall surface in a direction to the fully closed position of the acceleration pedal and thereby an excess force is applied to the forward end of the pedal rotating member. When a broken piece of the pedal rotating member (including the forward end thereof), which is a part of the pedal rotating member broken away from the boss portion, is moved inside of the supporting body of the acceleration device and brought into contact with the pedal shaft, a normal rotation of the pedal shaft may be adversely affected. As a result, the acceleration pedal (including the pedal shaft) may not return to the fully closed position thereof.